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NBDE II > OPERATIVE Instrumentation for Operative Dentistry Procedures > Flashcards

OPERATIVE Instrumentation for Operative Dentistry Procedures Flashcards

1
Q

what are the two preparation hand instrument categories?

A

cutting and noncutting

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2
Q

what are the 3 parts of a hand instrument?

A
  • handle, shank, and blade
  • for noncutting instruments, the part corresponding to the blade is called the nib, and the end of the nib (working surface) is called the face
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3
Q

operative cutting instrument formulas consist of 3 or 4 numbers separated by dashes. what do the numbers correspond to?

A
  • first number is the width of the blade or cutting edge in tenths of a mm (0.1mm)
  • second number of a 4-number code indicates cutting edge angle expressed as a percent of 360 degrees
  • third number of a 4-number code (or second number of 3-number code) is blade length in mm
  • fourth number (or 3rd number) indicates blade angle
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4
Q

___ instruments are used to cut hard or soft tissues of the mouth

A

cutting

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5
Q

___ are instruments used for removal of caries and refinement of the internal parts of the preparation

A

excavators

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6
Q

___ are instruments used primarily for cutting enamel

A

chisels

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7
Q

what are the four types of excavators?

A
  • ordinary hatchets
  • hoes
  • angle-formers
  • spoons
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8
Q

which type of excavator has the cutting edge of the blade directed in the same plane as that of the long axis of the handle and is bibeveled?

A

ordinary hatchet

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9
Q

ordinary hatchets are primarily used on ___ for ___

A

anterior teeth for preparing retentive areas

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10
Q

which type of excavator has the primary cutting edge of the blade perpendicular to the axis of the handle and is used for planing tooth preparation walls and forming line angles?

A

hoe

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11
Q

which type of excavator is a monangle instrument and has the primary cutting edge at an angle other than 90 degrees to the blade?

A
  • angle-formers

- they are available in pairs (R and L)

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12
Q

what are angle-formers used for?

A

sharpening line angles and creating retentive features in dentin and can also be used in placing a bevel on enamel margins

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13
Q

angle-formers may be described as a combination of a ___ and a ___

A

chisel and gingival margin trimmer

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14
Q

which type of excavator has slightly curved blades with cutting edges either circular or clawlike?

A

spoons

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15
Q

the circular edge of a spoon is called a ___, whereas the clawlike blade is termed ___

A

discoid, cleoid

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16
Q

spoon shanks may be ___ or ___ to facilitate accessibility

A

binangled or triple-angled

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17
Q

what are spoon excavators used for?

A

removing caries

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18
Q

what angle are the blades of chisels?

A

-straight, slightly curved, or binangle

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19
Q

where is the primary edge oriented in straight chisels? what other chisel is it similar in design to?

A
  • perpendicular to the axis of the handle

- carpenters chisel

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20
Q

what is the name of the design for a chisel with a slightly curved shank and blade?

A

wedelstaedt design

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21
Q

the force used with all chisels is basically a ___

A

straight thrust

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22
Q

what are 2 types of chisels?

A

enamel hatchets and gingival margin trimmers

23
Q

___ is designed to produce a proper bevel on gingival enamel margins of proximo-occlusal preparations

A

gingival margin trimmers

24
Q

what is the design of gingival margin trimmers?

A
  • similar to enamel hatchet except the blade is curved and the primary cutting edge is at an angle to the axis of the blade
  • right and left types
25
Q

cutting hand instruments such as the knife, file, and discoid-cleoid, are used for ___ rather than cutting tooth structure

A

trimming and carving restorative material

26
Q

what are the 6 hand instrument techniques?

A

modified pen grasp, inverted pen grasp, palm-and-thumb grasp, modified palm-and-thumb grasp, rests, guards

27
Q

rotational speed of an instrument is measured in RPMs. what are the 3 speed ranges that are generally recognized?

A
  • low/slow speeds (<12,000 rpm)
  • med/intermediate speeds (12,000-200,000 rpm)
  • high/ultrahigh speeds (>200,000 rpm)
28
Q

most useful rotary instruments are rotated at either ___ or ___ speeds

A

low or high

29
Q

what is the crucial factor for many purposes of rotary instruments?

A
  • surface speed of the instrument, which is the velocity at which the edges of the cutting instrument pass across the surface being cut
  • this is proportional to both the rotational speed and the diameter of the instrument, with large instruments having higher surface speeds at any given rate of rotation
30
Q

what are lasers used for in dentistry?

A

-primarily for either soft tissue applications or hard tissue surface modification

31
Q

why are lasers generally not used for tooth preparations?

A

because it is difficult to generated a defined margin or tooth preparation surface

32
Q

what is contemporary air-driven particle abrasion (air abrasion) useful for?

A
  • stain removal, debriding pits and fissures before sealing, and micromechanical roughening of surfaces to be bonded (enamel, cast metal alloys, or porcelain)
  • this works well when organic material is being removed and when only a limited amount of enamel or dentin is involved
33
Q

although air abrasion is promoted for caries excavation, why should it not be used exclusively in this way?

A

because it cannot produce well-defined preparation wall and margin details

34
Q

what are the common features all rotary cutting instruments share?

A

shank, neck, and head

35
Q

T or F:
the term shank when used to describe a rotary cutting instrument is not the same as when used to describe a hand instrument

A
  • true
  • the shank of a hand instrument connects the handle to the blade
  • the shank of a rotary cutting instrument is the portion that connects to the handpiece
36
Q

the term ___ is applied to all rotary cutting instruments that have bladed cutting heads

A

bur

37
Q

what are the 5 basic head shapes of burs?

A

round, inverted cone, pear shaped, straight fissure, and tapered fissure

38
Q

which bur head shape is spherical and is customarily used for initial entry into the tooth, extension of the preparation, preparation retention features, and caries removal?

A

round

39
Q

which bur head shape is a portion of a short tapered cone with the apex of the cone directed toward the bur shank, with the head length approximately the same as the diameter, and is particularly suitable for providing undercuts in tooth preparations?

A

inverted cone

40
Q

which bur head shape is a portion of a tapered cone with the small end of the cone directed toward the bur shank, with the end of the head either continuously curved or is flat with rounded corners where the sides and flat end intersect?

A

pear-shaped

41
Q

what type of pear shaped bur is advocated for tooth preparations?

A

long-length pear bur (length three times the width)

42
Q

which bur head shape is an elongated cylinder and is useful for amalgam tooth preparations?

A
  • straight fissure bur

- modified burs of this design with slightly curved tip angles are available

43
Q

which bur head shape is a portion of a tapered cone with the small end of the cone directed away from the bur shank and is used for tooth preparations for indirect restorations for which freedom from undercuts is essential for successful withdrawal of patterns and final seating of the restorations?

A
  • tapered fissure bur

- can have a flat end with the tip corners slightly rounded

44
Q

diamond instruments consist of what 3 parts?

A

metal blank, powdered diamond abrasive, and metallic bonding material that holds the diamond powder onto the blank

45
Q

the clinical performance of diamond abrasive instruments depends on what 5 things?

A
  • size, spacing, uniformity, exposure, and bonding of the diamond particles
  • increased pressure also removes more tooth structure
46
Q

what are the categories of diamond particle size?

A

coarse, medium, fine, and very fine

47
Q

effective and efficient cutting requires what 5 things?

A

powered handpiece, air-water spray for cooling, high operating speed (>200,000 rpm), light pressure, and a new carbide bur or diamond instrument

48
Q

what are the advantages of carbide burs?

A
  • end-cutting, produce lower heat, and have more blade edges per diameter for cutting
  • effectively used for punch cuts to enter tooth structure, intracoronal tooth preparation, amalgam removal, small preparations, and secondary retention features
49
Q

what are the advantages of diamond instruments?

A
  • greater hardness, and very high cutting effectiveness
  • more effective than burs for intracoronal and extracoronal tooth preparations, beveling enamel margins on tooth preparations, and enameloplasty
50
Q

the use of cutting instruments can harm the pulp in what ways?

A

exposure to mechanical vibration, heat generation, desiccation and loss of dentinal tubule fluid, and transection of odontoblastic processes

51
Q

what are the most frequent areas of soft tissue injury with cutting instruments?

A

lips, tongue, and cheeks

52
Q

describe possible hearing loss that can result from continued exposure to some air-turbine handpieces at high speeds?

A
  1. potential damage to hearing from noise depends on the intensity or loudness (decibels), frequency (Hz), duration of the noise, and susceptibility of the individual
  2. increased age, existing ear damage, disease, and medications are other factors that can accelerate hearing loss
53
Q

describe ways to avoid inhalation of aerosols and vapors produced by cutting tooth structure and restorative materials

A
  1. a rubber dam protects the pt against oral inhalation of aerosols or vapors, but nasal inhalation of vapor and finer aerosol may still occur
  2. disposable masks worn by dental office personnel filter out bacteria and all but the finest particular matter

NBDE II (35 decks)

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